Induced draft fan

ABSTRACT

An induced draft fan, including: a fan housing, a wind wheel, and an ECM motor including a motor body and a motor controller. The motor controller is a control board that is not enclosed in a control box. The control board includes a microprocessor unit, an IGBT switch and a drive unit thereof, a detection unit for detecting operating parameters of the motor, and a DIP switch unit. The detection unit transmits operating parameters of the motor to the microprocessor unit. The microprocessor unit outputs a signal to control the IGBT switch and the drive unit thereof. An output end of the IGBT switch and the drive unit thereof is connected to the coil winding of the stator. An output end of the DIP switch unit is connected to an input end of the microprocessor unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International PatentApplication No. PCT/CN2013/073176 with an international filing date ofMar. 26, 2013, designating the United States, now pending, and furtherclaims priority benefits to Chinese Patent Application No.201220315968.X filed Jun. 30, 2012. The contents of all of theaforementioned applications, including any intervening amendmentsthereto, are incorporated herein by reference. Inquiries from the publicto applicants or assignees concerning this document or the relatedapplications should be directed to: Matthias Scholl P.C., Attn.: Dr.Matthias Scholl Esq., 245 First Street, 18^(th) Floor, Cambridge, Mass.02142.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an induced draft fan.

2. Description of the Related Art

A typical induced draft fan, as shown in FIG. 1, is generally driven bya single phase motor PSC, and the single phase motor PSC is controlledby a system controller via a plurality of gear switch signals outputtherefrom. However, the single phase AC motor has low efficiency,relatively high energy consumption, large noise, and lowcontrollability. The technical scheme has poor compatibility, anddifferent application loads demand different compatible motors, therebyresulting in long development cycle, high management costs, poorversatility, and inconvenience in use.

An electronically commutated motor (ECM motor), including a DC brushlessmotor, a switched reluctance motor, and PMSM, is advantageous in energysaving, intelligence, high stability and controllability, and smallnoise. It is capable of regulating the output torque and the air volume,thereby shortening the development time and saving the developmentcosts.

Although the ECM motors have been utilized in the induced draft fan, itis troublesome to regulate the output power, the rotation torque, therotational speed, and the air volume of the ECM motor, which demandseither rewriting the control program of the motor by professionalprogrammers or replacing the motor, thereby being very inconvenient.

SUMMARY OF THE INVENTION

In view of the above-described problems, it is one objective of theinvention to provide an induced draft fan that adopts an energy-savingECM motor to substitute for the conventional single phase AC motor PSCand that is convenient for the user to regulate the operating parametersof the motor.

To achieve the above objective, in accordance with one embodiment of theinvention, there is provided an induced draft fan, comprising: a fanhousing, the fan housing comprising a surface; a wind wheel; and an ECMmotor, the ECM motor comprising a motor body and a motor controller. Themotor body comprises: a stator, a rotor, and a casing. The statorcomprises a coil winding. The rotor comprises a rotor shaft comprisingan end. The motor controller is a control board that is not enclosed ina control box (control box-free control board). The control boardcomprises: a microprocessor unit comprising an input end, an IGBT switchand a drive unit thereof comprising an output end, a detection unit fordetecting operating parameters of the motor, and a DIP switch unitcomprising an output end. The wind wheel is disposed inside the fanhousing. The ECM motor is disposed on the surface of the fan housing.The end of the rotor shaft of the rotor protrudes inside the fan housingand is connected to the wind wheel. The motor body is connected to themotor controller via an electric wire. The detection unit transmitsoperating parameters of the motor to the microprocessor unit. Themicroprocessor unit outputs a signal to control the IGBT switch and thedrive unit thereof. The output end of the IGBT switch and the drive unitthereof is connected to the coil winding of the stator. The output endof the DIP switch unit is connected to the input end of themicroprocessor unit.

In a class of this embodiment, the DIP switch unit comprises a pluralityof independent DIP switches.

In a class of this embodiment, a number of the DIP switches is betweenseven and twelve.

In a class of this embodiment, the microprocessor unit reads a signal ofeach DIP switch of the DIP switch unit to form a code set, selectsparameters of a rotational speed, a torque, and an air volume, andoutputs a signal to control the IGBT switch and the drive unit thereof.

In a class of this embodiment, the control board further comprises agear switch detection circuit. The gear switch detection circuit detectsa plurality of gear switch signals output by a system controller andtransmits the gear switch signals to the microprocessor. Themicroprocessor outputs a signal to control the IGBT switch and the driveunit thereof according to the gear switch signals.

In a class of this embodiment, the gear switch detection circuitcomprises a plurality of optical coupling isolation circuits.

In a class of this embodiment, the microprocessor unit is connected to acommunication port. The microprocessor unit communicates with a PCcomputer via the communication port. The PC computer sets or modifiesthe operating parameters of the motor in the microprocessor byprogramming.

Advantages according to embodiments of the invention are summarized asfollows:

1) The motor controller herein is a control board that is not enclosedin a control box. The control board is provided with the microprocessorunit, the IGBT switch and the drive unit thereof, and the detection unitfor detecting operating parameters of the motor. The control board isfurther provided with the DIP switch unit, the output end of which isconnected to the input end of the microprocessor unit. Themicroprocessor unit reads information of each DIP switch of the DIPswitch unit to form the code set, selects parameters of the rotationalspeed, the torque, and the air volume, and outputs signals to controlthe IGBT switch and the drive unit thereof. Thus, persons skilled in theart are not required to know how to program, they can set the coding ofthe DIP switch unit by utilizing the operation book to regulate theparameters of the rotational speed, the torque, and the air volume ofthe induced draft fan and the operation mode thereof, thereby beingsimple and convenient to meet the demands of the user.

2) The DIP switch unit comprises a plurality of independent DIPswitches. The number of the DIP switches is between seven and fifteen,so that relatively broad information is obtained from the code sets,thereby meeting the demands of the user.

3) The control board is further provided with the gear switch detectioncircuit that detects the gear switch signals of the system controllerand sends them to the microprocessor unit. The microprocessor unitoutputs the signal to control the IGBT switch and the drive unit thereofaccording to the gear switch signals, and is capable of communicatingwith the system controller and broadening the application range thereof.

4) The microprocessor unit is connected to the communication port. Themicroprocessor unit communicates with the PC computer via thecommunication port. The PC computer sets or regulates the operatingparameters of the motor in the microprocessor unit by programming,thereby being convenient for debugging the induced draft fan.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinbelow with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic diagram of a conventional induced draft fan;

FIG. 2 is a structure diagram of an induced draft fan according to oneembodiment of the invention;

FIG. 3 is a cross sectional view of an induced draft fan according toone embodiment of the invention;

FIG. 4 is a schematic diagram of an induced draft fan according to oneembodiment of the invention; and

FIG. 5 is a specific circuit block diagram of FIG. 4.

DETAILED DESCRIPTION OF THE EMBODIMENTS

For further illustrating the invention, experiments detailing an induceddraft fan are described below. It should be noted that the followingexamples are intended to describe and not to limit the invention.

As shown in FIGS. 2-5, an induced draft fan comprises: a fan housing 1,a wind wheel 2 disposed inside the fan housing 1, and an ECM motordisposed on a surface of the fan housing 1. The ECM motor comprises amotor body 3 and a motor controller. The motor body comprises: a stator31, a rotor 32, and a casing 33. An end 320 of a rotor shaft of therotor 32 protrudes inside the fan housing 1 and is connected to the windwheel 2. The motor body is connected to the motor controller via anelectric wire 5. The motor controller is a control board 4 that is notenclosed in a control box. The control board 4 comprises: amicroprocessor unit, an IGBT switch and a drive unit thereof, and adetection unit for detecting operation parameters of the motor. Thedetection unit transmits the operating parameters of the motor to themicroprocessor unit, and the microprocessor unit outputs a signal tocontrol the IGBT switch and the drive unit thereof. An output end of theIGBT switch and the drive unit thereof is connected to a coil winding ofthe stator. The control board 4 is further provided with a DIP switchunit 6. An output end of the DIP switch unit 6 is connected to an inputend of the microprocessor unit. The DIP switch unit 6 comprises aplurality of DIP switches, and a number of the DIP switches is betweenseven and fifteen. The microprocessor unit reads a signal of each DIPswitch of the DIP switch unit to form a code set, selects parameters ofa rotational speed, a torque, and an air volume, and outputs a signal tocontrol the IGBT switch and the drive unit thereof. The microprocessorunit is a micro controller unit (MCU) or a digital signal processor(DSP). The control board 4 further comprises a gear switch detectioncircuit. The gear switch detection circuit detects a plurality of gearswitch signals output by a system controller and sends the gear switchsignals to the microprocessor. The microprocessor outputs a signalaccording to the gear switch signal to control the IGBT switch and thedrive unit thereof. The gear switch detection circuit comprises aplurality of optical coupling isolation circuits.

The microprocessor unit is connected to a communication port. Themicroprocessor unit communicates with a PC computer via thecommunication port. The PC computer sets or modifies the operatingparameters of the motor in the microprocessor unit by programming.

Thus, persons skilled in the art are not required to know how toprogram, they can set the coding of the DIP switch unit by utilizing theoperation book to regulate the parameters including the rotationalspeed, the torque, and the air volume of the induced draft fan and theoperation mode thereof, thereby being simple and convenient to meet thedemands of the user. Definitions of different code sets of the DIPswitch unit are all recorded on the operation book, so that it isconvenient for the persons skilled in the art to directly set theoperating mode and parameters of the induced draft fan according toactual operating environment.

EXAMPLE 1

The DIP switch unit 6 comprises nine DIP switches. When the coding ofthe nine DIP switches is 001001111, the microprocessor unit reads theinformation of each DIP switch of the DIP switch unit. The coding001001111 means that the motor operates at a constant rotational speedof 1000 rpm. The microprocessor outputs a corresponding signal tocontrol the IGBT switch and the drive unit thereof.

EXAMPLE 2

The DIP switch unit 6 comprises nine DIP switches. When the coding ofthe nine DIP switches is 101011100, the microprocessor unit reads theinformation of each DIP switch of the DIP switch unit. The coding101011100 means that the motor operates at a constant torque of 400 N.m.The microprocessor outputs a corresponding signal to control the IGBTswitch and the drive unit thereof.

EXAMPLE 3

The DIP switch unit 6 comprises nine DIP switches. When the coding ofthe nine DIP switches is 110011001, the microprocessor unit reads theinformation of each DIP switch of the DIP switch unit. The coding110011001 means that the motor operates at a constant air volume. Atorque is 600 N m, and a rotational speed is 800 rpm. The microprocessoroutputs a corresponding signal to control the IGBT switch and the driveunit thereof.

While particular embodiments of the invention have been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention inits broader aspects, and therefore, the aim in the appended claims is tocover all such changes and modifications as fall within the true spiritand scope of the invention.

The invention claimed is:
 1. An induced draft fan, comprising: a) a fanhousing, the fan housing comprising a surface; b) a wind wheel; and c)an ECM motor, the ECM motor comprising a motor body and a motorcontroller; the motor body comprising: a stator, a rotor, and a casing;the stator comprising a coil winding; the rotor comprising a rotor shaftcomprising an end; the motor controller being a control board that isnot enclosed in a control box; the control board comprising: amicroprocessor unit comprising an input end, an IGBT switch and a driveunit thereof comprising an output end, a detection unit for detectingoperating parameters of the motor, and a DIP switch unit comprising anoutput end; wherein the wind wheel is disposed inside the fan housing;the ECM motor is disposed on the surface of the fan housing; the end ofthe rotor shaft of the rotor protrudes inside the fan housing and isconnected to the wind wheel; the motor body is connected to the motorcontroller via an electric wire; the detection unit transmits operatingparameters of the motor to the microprocessor unit; the microprocessorunit outputs a signal to control the IGBT switch and the drive unitthereof; the output end of the IGBT switch and the drive unit thereof isconnected to the coil winding of the stator; and the output end of theDIP switch unit is connected to the input end of the microprocessorunit.
 2. The induced draft fan of claim 1, wherein the DIP switch unitcomprises a plurality of independent DIP switches.
 3. The induced draftfan of claim 1, wherein a number of the DIP switches is between sevenand twelve.
 4. The induced draft fan of claim 1, wherein themicroprocessor unit reads a signal of each DIP switch of the DIP switchunit to form a code set, selects parameters of a rotational speed, atorque, and an air volume, and outputs a signal to control the IGBTswitch and the drive unit thereof.
 5. The induced draft fan of claim 1,wherein the control board further comprises a gear switch detectioncircuit; the gear switch detection circuit detects a plurality of gearswitch signals output by a system controller and transmits the gearswitch signals to the microprocessor; and the microprocessor outputs asignal to control the IGBT switch and the drive unit thereof accordingto the gear switch signals.
 6. The induced draft fan of claim 2, whereinthe control board further comprises a gear switch detection circuit; thegear switch detection circuit detects a plurality of gear switch signalsoutput by a system controller and transmits the gear switch signals tothe microprocessor; and the microprocessor outputs a signal to controlthe IGBT switch and the drive unit thereof according to the gear switchsignals.
 7. The induced draft fan of claim 3, wherein the control boardfurther comprises a gear switch detection circuit; the gear switchdetection circuit detects a plurality of gear switch signals output by asystem controller and transmits the gear switch signals to themicroprocessor; and the microprocessor outputs a signal to control theIGBT switch and the drive unit thereof according to the gear switchsignals.
 8. The induced draft fan of claim 4, wherein the control boardfurther comprises a gear switch detection circuit; the gear switchdetection circuit detects a plurality of gear switch signals output by asystem controller and transmits the gear switch signals to themicroprocessor; and the microprocessor outputs a signal to control theIGBT switch and the drive unit thereof according to the gear switchsignals.
 9. The induced draft fan of claim 5, wherein the gear switchdetection circuit comprises a plurality of optical coupling isolationcircuits.
 10. The induced draft fan of claim 6, wherein the gear switchdetection circuit comprises a plurality of optical coupling isolationcircuits.
 11. The induced draft fan of claim 7, wherein the gear switchdetection circuit comprises a plurality of optical coupling isolationcircuits.
 12. The induced draft fan of claim 8, wherein the gear switchdetection circuit comprises a plurality of optical coupling isolationcircuits.
 13. The induced draft fan of claim 5, wherein themicroprocessor unit is connected to a communication port; themicroprocessor unit communicates with a PC computer via thecommunication port; and the PC computer sets or modifies the operatingparameters of the motor in the microprocessor by programming
 14. Theinduced draft fan of claim 6, wherein the microprocessor unit isconnected to a communication port; the microprocessor unit communicateswith a PC computer via the communication port; and the PC computer setsor modifies the operating parameters of the motor in the microprocessorby programming.
 15. The induced draft fan of claim 7, wherein themicroprocessor unit is connected to a communication port; themicroprocessor unit communicates with a PC computer via thecommunication port; and the PC computer sets or modifies the operatingparameters of the motor in the microprocessor by programming.
 16. Theinduced draft fan of claim 8, wherein the microprocessor unit isconnected to a communication port; the microprocessor unit communicateswith a PC computer via the communication port; and the PC computer setsor modifies the operating parameters of the motor in the microprocessorby programming.